Combined gravity and vacuum carburetor



J. A. SPEED.

COMBINED GRAVITY AND VACUUM CARBURETOR.

APPLICATION FILED DEC.2'I, 1919. 1,409,420. Patented 14, 1922;.

3 SHEETSSHEET ln l5: .IW. w H Ill 0 I m F I k 3 ix fi I 5 J. A. SPEED.

' COMBINED GRAVITY AND VACUUM CARBURETOR.

APPLICATION FILED DEc.27.1919.

3 SHEETS-SHEET 2.

1,409,420, 7 Patented Mar.14,1922.

J. A. SPEED.

COMBINED GRAVITY AND VACUUM CARBURETOR.

. APPLICATION FILED DEC. 27. 1919. 1,409,420.

Patented. Mar. 14, 1922.

3 SHEETSSHEET 3. F H H I I I UNITED STAT S PATENT OFFICE.

.mmss A. srmm, or SAN FRANCISCO, CALIFORNIA.

(lOMBINED GRAVITY AND VAGU'UllE CARBURETOR.

To all whom it may co'r'wem:

Be it known that I, JAMES A. SPEED, a citizen of the United States, anda resldent of the city and county of San Francisco, State of California,have invented new and useful Improvements in Combined Gra ity and VacuumCarburetors, of which the ollowing is a specification.

My invention has for its object the automatic and continuous supply ofgasoline, or other hydro-carbon fuel, at all times and 1n accordancewith the requirements of an engine in which it is contemplated to usethe said fuel, as the well known automobile or internal combustionengine.

As is well known, the use of a hydro-carbon fuel contemplates themixture of air with the said fuel in a gasified form whereby theexplosive mixture is obtained; also, that under different conditions asof load, temperature and humidity, variations in the constituents of thesaid mixture are frequently advisable In the carburetor of my inventionI feed the hydrocarbon fuel from the main supply tank by gravity to thecarburetor, unless for any reason, as that due to the change in therelative elevation of the main supply tank and carburetor, the action ofgravity is absent or not sufficient to causethe fuel to pass into thecarburetor, or is not sufficient to cause the fuel to pass withsufficient rapidity into the "carburetor, in which case the mechanism ofmy invention operates to produce a negative or vacuum pressure withinthe carburetor chamber to withdraw the:

fuel from the main supply tank to at all times meet the requirements ofthe fuel demand through the said carburetor and thus meet the engineneeds.

Anotherobject of my invention is to, at all times, proportion thesupplyof air for the explosive mixture and fuel quantity in a proper ratio tosecure the best possible results from the mixture. These objects Iaccomplish by utilizing .the suction pressure from the engine throughthe carburetor to withdraw the fuel from the main tank to the carburetorwhenever the rate of flow of said fuel is retarded, due to any cause, asthe reduction in relative elevation between the main fuel tank-and thecarburetor, and- I provide a form of throttle valve which ad mits underthe control of the said valve 'a variable quantity of mixing air, andthrough Specification of Letters Patent.

4 buretor.

Patented Mar. 14, 1922.

Application filed December 27, 1 919. Serial No. 347,768.

ports controls the providing of a momentary additional fuel supply tosecure quicker engine acceleration upon any further opening of thethrottle valve, after whichthe rate of flow isautomatically 'reducedto'the point of efficient supply for the newly attained speed or load ofthe engine. This object I attain by the use of a plurality ofsupplementary wells within each of which a small supply of fuel isretained until the fuel valve ports communicating with the said wellsare opened. Upon the further opening of the throttle valve whenaccelerating the supply of the corresponding well is instantly admitted,and' until exhausted, after which a previously calibrated or restrictedflow of the fuel to the well limits the rate of further fuel supply; thesaid calibrated or restricted rate, being properly proportioned to thenormal engine requirements at the speed or load corresponding with thethrottle valve setting communicating with the said well or wells.

Other objects will appear from the drawings and description whichfollow:

'By referring to the accompanying drawings my invention will/be madeclear.

Fig. 1 is a cross section through my car- Fig. 2 is a plan thereof. i

.Fig. 3 is a horizontal section through my carburetor on the lineIII-III of Fig. 1. Fig. 4 is a section on the line IV-IV of Fig. 1. Fig.5 is a front view of the throttle face of the well casing 3.

Fig. 6 is a view of the throttle valve and plate. 56 assembledtherewith.

Fig. 7 is a right angle view of Fig. 6. Fig. 8- is a cross section ofFig. 1.on the line VIII-VIII.

Figs 9 and 10 are details in section showing variations in thearrangement of the wells and valved means connected therewith.

Fig. 11 is an enlarged section of the up per portion of the chamber 29and associated parts of Fig. 1.

Throughout the figures the same numerals refer to identical parts. 4

Referring now particularly to Fig. 1, the throttle valve is indicated bythe numeral 1, surrounded by the casing 2, which casing is constructedand adapted to assemble with the well housing 3, which I prefer to formwith a float chamber 4, within which is provided the usual form of float5 and valve 6, which latter is adapted to be actuated by the said floatto control the port 7. 1

The port 7 receives its fuel through the passage 9 from the duct 10after passing the check valve 11, preferably mounted in the chambercover 12. Within this cover, or in other suitable upper portion adjacentthe chamber 4, I provide an air vent .13.

The walls of the chamber 4 are provided with a suitable recess as at 14for receiving the top member 29, within which I mount the secondaryfloat 15, which carries the main valve 16.

spring, as indicated at 17, fromthe said secondary float. Main valve 16is adapted to normally close vacuum port 18, unless the fuel levelsustaining the secondary float 15 drops below a predetermined point, atwhich time valve 16 is withdrawn from the port 18 and the vacuum, ornegative pressure from the passage way 19 is opened through the passage20, admitting said negative to the secondary float chamber 29.

The main fuel supplyis connected at the fuel inlet 54, from a suitabletank and by suitable pipe connections not shown, but well known, fromwhich inlet the fuel may be passed ,by the check valve 21, passage 22,into the secondary float chamber 29.

At 23 (see Fig. 11) I provide a vacuum check valve, and at 24 a fuelcheck valve, preferably made of cork. These two latter valves aremounted in tandem in a passageway 25 communicating with vacuum passage26 by the vacuum valve 27, the latter being normally held open when fuelis supplied to the secondary float chamber 29 by.

gravity, and the said vacuunr'pressure holding the ball 23 agalnst itsupper seat 76*allowing air communication through vent 75 to chamber 29.At such time the. main valve 16 is held against the Seat 18.

The vacuum valve 27 closes the vacuum passage 26 due to the falling ofthe main valve 16, the latter being withdrawn from the port 18, by thesecondary float15 whenever the latter drops with a reducing fuel levelin the s'econdaryfloat chamber 29.

Connecting'with the float chamber 4 by the duct 30 are a plurality ofwells as 31, 32,

pressure I more or less the said channel ways through the thin platewill consecutively expose the said fuel-passage-conduit-outletsadmitting communication to the fuel nozzzle 39 from one or more of thesaid wells 31, 32, 33, 34

according to the engine requirements.

It will be noted that the throttle casing 2 may be assembled about thecircular joint 40 in several positions so as to retain the floatchambers 4 and-29 vertical, although the engine suction inlet 41 may bein any of several different positions to suit the manifold connections.a

At 42 is provided a suction port co-operating with'the groove 43 in thecircular joint 40, which groove communicates by the passage 44 with thevacuum passage 19 of the assembled carburetor.

- Within the wells, as 31, 32, 33,34 (see Fig. 4) I provide screw plugswith cali- Th1s latter I prefer, to suspend by a brated ports 45, whichare provided with fuel passages of predetermined size 46, which ginesuction.

The air to mix with the fuel is provided through air inlet shown at 47,and the passageway for the said air I prefer to make tapering to athroat at 48, which passageway again tapers outward to the enginesuction inlet at 41. The incoming air therefore attains its highestvelocity .at 48, just beyond which point is located the fuel nozzle orother fuel. outlet 39. The fuel flowing from the said nozzle istherefore picked up by the inrushing air, while the air is at itsmaximum velocity, and is then thoroughly atomized and vaporized duringits passage 5 upward in the direction of the arrow 49, and

within the tapering passage.

It is to be understood that the throttle 1 is substantially cylindrical,or conical, rotatable about the joint 50, so that the passage from 47 to41 may be-entirely closed off or opened to any degree by the throttle 1,and that any opening from the fuel nozzle 39 to the engine suction inletby the joint 50 will provide also a corresponding openin but preferablyof slightly less area from t e air inlet to the throat 48. v

, would otherwise occur.

Referring specifically to Figs. 9 and 10,

I prefer to make the dimension 51 slightly greater than the dimension at52 to compensate for the increased volume due to the vaporization of thefuel. For idling, I prefer to form an air passage as at 53, (see Fig. 8)which is opened by the throttle valve to the throat during such times asthere would otherwise be complete closure of the air inlet. It isunderstood that this passage 53 may be made adjustable in any well knownway so as to properly adjust for the idling condition of the particularengine to which the carburetor is being adapted.

- At 55 I have shown a port communicating also with the vacuum passage19 (see Fig. 1) and an outlet to which passage is in the neck of thethroat. This is for the purpose of securing the vacuum draft in thepassage 19 at times when the throttle is wide open, or nearly so. Suchconstruction is advisable when the vacuum in the manifold has dropped toan unusual degree asis the case in some engine constructions.

At 56 .(see Figs. 6 and 7) is located a thin plate, having ports asindicated at 82, 83, 84, 85 and which port/s open into the annulargrooves 58, 59 of the member 1. These annular grooves are crossconnected so that both of them feed to the nozzle 39, the thin plate 56controlling the fuel flow from the well passages 35, 36, 37, 38 of Fig.5 into the groove ports 58, 59 in Figs. 7 and 3. The thin plate 56 isprovided with a pin, 60, which is adapted to engage with any one ofseveral holes as 61, 62, 63 in the member 1, by which I am enabled toset the throttle 1 and its casing 2 in any required position withrelation to the carburetor engine manifold and at the same time retainthe relation of the thin plate 56 with its ports to the correspondingface of the well housing '3. The passageway through the member 1 isconstructed as shown at 48 (see Figs. 1 and 8) for the purpose ofmaintaining a relatively high air velocity to facilitate the picking upof the fuel from the nozzle 39, and also causing its rapidvolatilization, and the said passage is tapered on each side of saidneck or restriction to avoid losses which I have shown at 64 a form ofported screw plug pierced through its center and located in the well as31, so that upon a demand for fuel being caused by the setting of thevalve 1 through the passageway 65 to the nozzle 39, fuel will be firstwithdrawn from the well through the-opening 66 thus providing an excessfuel for the acceleration period corresponding with the new throttleposition, and thereafter fuel will flow throughthe valve inlet at 67 Allof the fuel flowing through the passage 64 will find its way into theupper compartment 68 and thence through the passage It is obvious thatupon the first demand upon any well being made for fuel, there will bewithdrawn some ofthe fuel from the well, resulting in a momentaryincreased flow therefrom, which I utilize as extra fuel during theacceleration period of the engine to' its new speed, or load. Theabstraction of this fuel from the well will. cause a slight negativepressure above the fuel to reduce its rate of flow as the speed due toacceleration is increased, and which is a desirable result. If, however,the volume of air above the fueljn the well is small I prefer to providea limited or restricted air inlet, thereby permitting the abstraction ofthe fuel from the well through the nozzle 39 at a greater rate. Such airinlet is not shown but is well known.

Or, the well 31 may be provided with a relatively large air capacity sothat the abstraction of fuel upon the opening of the port communicatingwith the well will permit the expansion under a very low vacuum draft ofthe said large air volume. Such a relative proportion of Well volumecontaining the air and the fuel is shown in Fig. 10, or the well may bemade shorter and a valve or diaphragm may be allowed to float on thesurface 78 so that the fuel contained in 31 as it is abstracted, due tothe opening of the corresponding port by the throttle 1, will fall untilthe said float valve rests upon the pins 79. In such a case the well '31may be made quite short as to the line 80, and

an air inlet provided as indicated at 81 in dotted lines, the floatvalve 78 serving as a diphragm, or piston floating on the surface of thefuel and effectually closing the .air passage of the fuel chamber; orother forms of valve or air chamber permitting the abstraction of thefuel in the well and its restoration under gravity from the chamber maybe substituted and obtain the same results and I desire to be understoodas claiming all such modifications.

If for any reason fuel does not flow into chamber 29 by gravity, float15 will fall producing, a spring pressure against valve 16,

which pressure when suflicient withdraws the ball 23, closing port 76.

' If fuel flows by gravity through the inlet 54 by the check 21 andthrough the passageway 22, adequately supplying the chamber 29, thevalve '16-is retained upon its seat and fuel will flow into chamber 29until such time as the float valve 24 is carried by the said fuel toclose the port 25.

It will be noted that there is a possible intermediate condition whichmay exist due to a change in the relative position of the supply tankafter the chamber 29 has been filled by gravity, and during whichcondition the fuel contained in the chamber 29 will be graduallywithdrawn through the passage 10 and the ball 23 will be retained uponthe seat 7 6 due to the engine operation and maintenance of vacuum inthe passage 26, and to permit the withdrawal of the said fuel from thechamber 29 it is necessary to open the said chamber to the atmosphere.This is accomplished by the float valve 24 falling away from the seat 25thus admitting atmospheric pressure through the passageway 75, so as toallow air to replace the fuel. being withdrawn.

The operation is as follows:

Upon a demand for fuel from the engine and throttle valve 1 beingrotated about the joint 50, admitting air as at the inlet 47 andadmitting fuel through the nozzle 39 from one or more of the .wells 31,32, 33, 34, the action will be as above described to supply the excessfuel momentarily, or during the period of engine acceleration andthereafter to restrain the rate of fuel flow through the nozzle 39 to apredetermined required amount to sustain the engtines speed or load. Thefuel supply through the nozzle 39 is thereafter supplied from thechamber 4, through the passageway 30, and through one or more of therestricted valved ports of the wells.

When the fuel supply from the chamber 4 has been abstracted to asufiicient degree float 5 falls withdrawing valve 6 from the port 7 andfuel is then admitted through the passageway 10 by the ball check'll,passage 9 and out through the openings 8, restoring the fuel supply inthe chamber 4. 5

When the fuel has been withdrawn from chamber 29--through the passageway10, as above described, additional fuel is supplied to the chamber 29,either by gravity, supplied through the inlet 54 by the ball check 21,and through passage 22. Or, if for any reason fuel does not flow underthe action of gravity in this way to maintain float 15 in its elevatedposition, the said float 15 will then drop, withdrawing the valve 16 andadmitdraw fuel through the passage 22 by the check valve 21 and maininlet supply 54 until the float 15 is raised to the required height toclose passage 18 by the valve 16. 7

When the said valve is closed the ball 23 will be retained by the vacuumcommunicated through the passage 26 upon its seat at 76 and air inlet 75 will be opened through port 25 by the valve 24 to the said chamber 29,unless the said chamber 29 is entirely filled with fuel, in which casethe valve 24 will float upward and close port 25.

It is to be understood that the throttle valve is to be operated in thewell known way by the rotation of the spindle 86, and lever 87,connected to suitable hand or foot controlling devices, not shown. Therotation of the throttle demands a greater or less quantity ofcarburant, or ex losive mixture to the engine manifold. pon a rotationto a greater opening of the said throttle, the additional carburant ismomentarily enriched by the abstraction temporarily of the extra fuelcontained in one or more of the wells, and thereafter, assuming thethrottle position as not again changed, the rate of fuel flow throughthe valved or restricted passages from the fuel chamber to the wells,the rate of fuel fiow into the throttle and mixing passages will be suchas to establish and maintain a carburant of the most eflicient mixtureto sustain the newly acquired engine speed or load.

I claim- 1. In a carburetor,

a substantially c lindrical throttle valve,

having a relatively small passage therethrough, a casing having inletand outlet passages cooperating with said throttle passage, said inletpassage tapering to the smaller throttle passage and said outlet passagetapering outward therefrom, in combination with a fuel chamber, and aninitial fuel chamber, a duct between said chambers, a fuel supplyconnection to said initial chamber, a float in said initial chamber, avacuum duct in communication between said initial chamber and the saidoutlet passage, a valve in said duct actuated by said float when thefuel level therein varies from a predetermined height, a connectionbetween the two chambers and a valve therein actuated by a float,mounted in the fuel chamber whereby the said passage is opened to admitthe flow of fuel from the initial chamber to the fuel chamber upon areduction in the elevation of fuel in the fuel chamber below apredetermined level.

2. A carburetor comprising parts as set forth in claim 1 and a pluralityof wells each having a restricted inlet and an enlarged outletand a portthrough the said throttle and into the small passage therein constructedand adapted to register with one or more of said enlarged outletsdepending on the position of the throttle.

3. A carburetor comprising parts as set forthin claim 1 and a pluralityof wells each having a restricted inlet and an enlarged outlet and aport through the said throttle and into the small passage thereinconstructed and adapted to register with one or more of said enlargedoutlets depending on the position of the throttle and an independenltlyadjustable valve in each rest-rictedwell in et.

In testimony whereof, I have hereunto set my hand at San Francisco.California.

JAMES A. SPEED.

